docs: add project explanation and handoff guide

.project-docs/30-worklog/current-state.md

@@ -19,6 +19,17 @@ preserves its no-formula contract. Both publishers upload new workbook and `resu
 immutable OSS adapter, while download routing retains controlled-local compatibility for historical records and keeps
 `.web-jobs` queue state local.
 
+## Documentation And Repository Handoff On 2026-09-06
+
+- Added root `PROJECT_GUIDE.md` as a Chinese project explanation and handoff guide. It consolidates the project goal,
+  architecture, XML/manual-review/monthly/Booking/company-report/BI flows, module map, configuration, local startup,
+  migrations, tests, deployment, troubleshooting, security boundaries and new-member checklist. The root README links
+  to it as the complete project entry point.
+- The guide explicitly separates repository implementation from production deployment and business acceptance, and
+  routes changing operational gaps back to `90-maintenance/stale-items.md`. Local Markdown links, Git whitespace and
+  the documented Web/worker CLI entry points pass. This documentation-only task changed no application behavior,
+  database, object store, runtime process or business data.
+
 ## Daily Interaction Correction On 2026-08-11
 
 - The local source now treats Daily Report rows as informational table rows rather than hidden log controls. It removes

.project-docs/30-worklog/task-history.md

@@ -4,6 +4,7 @@
 
 | Date | Task | Outcome | Docs Updated |
 |---|---|---|---|
+| 2026-09-06 | Create a project explanation/handoff document and publish the repository | Added `PROJECT_GUIDE.md` with the business purpose, architecture, six main flows, ownership boundaries, modules, configuration, local operation, migrations, testing, deployment, troubleshooting, security and handoff checklist; linked it from README and kept unresolved deployment/business acceptance items explicit. Local links, Git whitespace and Web/worker CLI help pass. No application, database, OSS, runtime or business state changed | `PROJECT_GUIDE.md`, README, current state, task history, scoped planning record |
 | 2026-08-11 | Implement Lian Tai/QBD bilingual Booking-header compatibility | Bumped the bounded parser to 2.1.0, converted readable approved header labels into the existing exact normalized allowlist, preserved legacy aliases and fail-closed ambiguity, and added Chinese/English/Thai header-error mapping. Synthetic parser/coordinator tests, all four supplied workbook replays and wrong-report negatives pass; no API, migration, upload, draft, source activation or runtime deployment occurred | README, architecture/data-flow/business rules, current state, [header-parse evidence](../50-evidence/topics/2026-08-11-company-channel-booking-header-parse-failure.md), evidence index, stale deployment item |
 | 2026-08-11 | Make the top-right control the sole Daily task-log entry | Removed concrete-row click/Enter/Space log activation plus the row's button semantics, pointer, focus and selected styling. Explicit download and manual-review controls remain; isolated browser QA proved ordinary row → no dialog, review control → focused operation panel, header `任务日志` → dialog. JavaScript syntax and all 81 Web tests pass. The source is local and production deployment is still pending | Success criteria, current state, [interaction evidence](../50-evidence/topics/2026-08-11-daily-row-task-log-entry-boundary.md), evidence index, stale deployment item, scoped planning record |
 | 2026-08-11 | Plan Lian Tai/QBD bilingual Booking-header compatibility | Verified the exact supplied header cells and rendered header-only ranges. Current parser 2.0.0 rejects both; an in-memory exact three-alias expansion parses only the intended sheets (Lian Tai 67/100/16 pending; QBD 104/218/212 pending) while two report-output negatives remain rejected. Recommended parser 2.1.0, synthetic parser/coordinator regressions, neutral error copy and docs; no migration/UI redesign. One-file/full-replacement activation remains a separate operational boundary. No code, workbook, database or runtime changed | Current state, [header-parse evidence](../50-evidence/topics/2026-08-11-company-channel-booking-header-parse-failure.md), evidence index, stale item, scoped planning record |